Piezoelectric crystal mounting



Feb. 18, 1947. C, G, ROBB ErAL 2,416,067

PIEZOELECTRIC CRYSTAL MOUNTING Filed Sept. 12, 1945 INSULA TION Patented Feb. 18, 1.94.7

PIEZOELECTRIC CRYSTAL MOUNTING Charles'G. Robb, Glastonbury, and Sydney'E. Warner, East Hartford, Conn., assignors to `Crystal Research Laboratories, Inc., Hartford,

Conn., acorporation of Connecticut Application September 12, 1945, Serial No. 615,848

10 Claims. l

The invention relates particularly to a piezoelectric crystal mounting adapted for use under conditions of severe external mechanical shock and vibration, and the principal object of the iness. The shape, size and other characteristics of 2 the crystal do not constitute any part of the present invention.

For supporting the crystal I8 on the supports I4, I4 and for providing electrical connections,

vention is to provide a crystal unit or assembly 5 there are provided two preferably similar resilient wherein the crystal is so mounted and held as to supporting and conducting elements 22, 22. Each receive the minimum of external shock and v ibraof the elements 22, 22 is formed of wire and is tion and is protected to the maximum extent suitably connected at its outer end with the corfrom stresses resulting therefrom, responding support I4 and is soldered at itsinner A further major object of the invention is to end, as indicated at 24, 24, to the corresponding provide a crystal mounting which prevents vibrametallic coating 0n the Crystal I8. In order tion of the crystal in resonance with the elements '00 `alfiSOrb external mechanical Shock each elewlneh directly support it ment 22 preferably comprises a coil spring which Other objects of the invention are to provide may advantageously be conical in Shape With its certain improved details of mechanical structure l5 outer end at the outside and directly attached whereby the before-stated principal objects are by Scldering 01 Otherwise t0 the Corresponding attained support I4. The inner end of each element 22 Still other objects of the invention will be apadjacent the Solder cOnncciOn 24 iS preferably parent from the following specification and from Straight and perpendicular i0 the corresponding the attached drawing. 20 face of the crystal.

0f the drawing, In order to prevent the resilient supporting ele- Fig. 1 is a combined side and sectional view of ments 22, 22 from vibrating independently of a crystal mounting embodying the invention, the each other with resultant disruptive eiect on the sectional portion of the view being token along a crystal itself or on the solder connections at 24, central vertical plane. 25 24, there is provided an insulating U-shaped yoke Fig, 2 is a plan view with the outer protecting 26 which embraces the crystal and which has its oover omitted, end portions or legs mechanically connected di- Fig. 3 is an enlarged perspective view-of one of reCiily With the respective SuDDOrting elements the elements of the mounting, 22, 22. Preferably, and as shown, the/ straight Fig. 4 is an enlarged perspective view showing 30 inner end portions of the supporting elements an element of the mounting which may be used 22, 2 2 extend through slots 28, 28 in the legs of 8S en alternative t0 that shown in Fig. 3. the yoke and are soldered to the said legs as Referring to the drawing, i0 is an insulating indicated at 30. The slots 28, 28 make it possible base for supporting the other elements, this base fOr the yoke t0 be nut in piace after the support'- being preferably circulan projecting from the ing elements or wires 22 have been soldered to the bottom of the base I0 are two spaced terminal CryStaL pins I2, I2. Portions of the pins I2, I2 extend AS ShOWn in FigS- 1, 2 and 3, 'Shel/Oke 26 00mthrougn the bese and have threaded engagement prises two. separate metallic sections 32y and 34 with two upright Supports i4, M Preferably, in which are spaced apart and are connected by an order to insure good electrical connection, solder insulating section 36. As Shown', the metallic joints are provided at I6, IB, between the sup- Sections 32 and 34 are provided with integral ports I4, I4 and the terminal pins I2, I2, prongs 38, 38 and 40, 40 which enter notches in The crystal is shown at isiend it may be the insulating section 36 and are crimped over to formed of quartz. The crystal has the required rigidly nOld the three sections in nxed relationdimensions and characteristics to enable it td 45 ship with each other. It will be seen that the vibrate at a. predetermined frequency, and it may yoke 2B'Drovides a mechanical connection around be designed to have a face shear mode of vibrathe Crystal between the inner ends 0f the Suption- In accordance with recognized practice in porting elements 22, 22, With011i5,h0WeVer.Dr0Vd the preparation ofr crystals, the crystal I8 has lng any electrical connection between the'two y opposite conductivev electrode coatings 20, 20, supporting elements. which may consist of any suitable metal such as As an alternative to the yoke 26 shown in silver, copper, aluminum, gold, or platinum, and Figs. 1, 2 and 3, a yoke 42 may beprovided, as may be applied to the crystal surfaces by evaposhown in Fig. 4, which is formed entirely Vof inration in4 vacuum or by any other suitable procsulating material and which has two metallic inserts 44, 44 therein. These inserts are prefducting elements I2, I4 and 22.

arreter erably eyelets with apertures 46, it therein. The eyelets 44, M are crimped or upset to firmly grip the walls of the legs of the yoke 42 and they provide means for the attachment of solder connections such as the solder' connections 3D, 30 shown in Fig. 1. The apertures 46, 46 correspond in function to the slots 2B, 28 in the yoke 26, but it is necessary for the supporting elements or wires 22, 22 to be inserted through the apertures before they are soldered to the crystal.

Preferably, the crystal I8 and the'. supporting means therefor are-enclosed by a metal cover -48 which ts around the 'base i0, a gasket 50 of rubber or other suitable material being interposed between the top of the base and a shoulder on the cover. The lower edge of the cover 48 is crimped inward to engage the base and hold the cover firmly in place.

It will be seen that withA the construction described, the crystal is resiliently supported between the two supports I4, I4 soy as to receive a minimum of any external shock or vibration to which the unit `as a whole may be subjected. It will be observed that the legs of the yoke are substantially spaced from the faces of the crystal with short intervening lengths of wire between the said legs and the said faces. The crystal is free to vibrate at its predetermined inherent frequency in accordance with electrical impulses imparted thereto through one set of `the con- The yoke which connects the inner end portions of the supporting elements 22, 22 holds these two inner end portions in iixed relationship to each other so that the crystal is entirely protected from those stresses to which it might lbe otherwise subjected by reason of .vibrations of the supporting elements or wires 22, 22. If the connecting yoke were not provided, the two supporting elements would tend to vibrate in resonance and 'this vibration would be transmitted to the crystal. Inasmuch as the yoke rigidly connects the supporting wires at opposite sides of the crystal, resonant vibration of the wires cannot be transmitted to the crystal.

While we have shown and described a certain preferred vem-bodiment of our invention, modifica# tions thereof will readily occur to those skilled supports on the base at yopposite sides of the crystal, and two resilient supporting and conducting wires soldered at their respective inner ends to the metallic coatings on the crystal, each of the Lsaid wires including a coil directly connected at its outer end to the corresponding support.

4. The combination in a piezoelectric crystal unit, of a crystal `having metallic coatings on its opposite. major faces, an insulating base, two supports on the base at opposite sides of .the crystal, and two resilient supporting and conducting wires having straight inner portions perpendicular to the metallic coatings on the crystal and soldered thereto, each of the said wires also including a coil'directly connected at its outer end to the corresponding support.

5. In a piezoelectric crystal unit, the combination of a crystal having metallic coatings on its opposite major faces, an insulating base, two supports on theV base at opposite sides of the crystal, two resilient supporting elements of conducting material mechanically and electrically connected at their respective outer ends with the supports ments of conducting material mechanically and f electrically connected at their respective outer ends with the supports and soldered at their respective inner endsto the metallic coatings on the crystal, and an insulating U-shaped yoke embracing the crystal and having its end portions mechanically connected wth the respective supporting elements adjacent the crystal.

in the art, and we therefore intend our in vention to be limited only by the appended claims.

What we claim is: 1. The combination in a piezoelectric crystal unitl of a crystal having metallic coatings on 'its opposite major -faces, an insulating base, two/- supports on the base at `opposite sides of the crystal, and two resilient supporting and conducting elements mechanically andy electrically connected at their respective outer ends with the supports and soldered at their respective inner ends to the metallic coatings on the crystal, each of the said elements comprising a coil spring.

2. The combination in a piezoelectricfcrystal unit, of a crystal having metallic coatings on its opposite major faces, an insulating base, two

supports on the base at opposite sides of the crystal, and two resilient supporting and conducting elements soldered at their respective inner ends to the metallic coatings on the crystal, each of the said elements comprising a conical coil'sprng having its larger outer end mechanically and electrically connected with the corresponding support.

3. The combination in a piezoelectric crystal` unit, of a crystal having metallic coatings on its opposite major faces, an4 insulating base, two

mechanically connected with the respective supporting elements adjacent'the crystal.

8. In a piezoelectric crystal unit, the combination of a crystal having metallic coatings on its I opposite major faces, an insulating base, two supports on the base at opposite sides of the crystal, tworesilient supporting wires of conducting material having straight inner portions perpendicular to4 the respective metallicscoatings on the crystal and soldered thereto, each 'of the said wires also including a coil directly connected at eombinatiom a crystal having metallic coatings,

on its opposite major faces, an insulating base, two supports on the base at opposite sides of the crystal, two resilient supporting elements of conducting material mechanically and electrically connected at their respective outer ends wlththe supports and soldered at their respective inner ends to the metallic coatings on the crystal, and a U-shaped yoke embracing the crystal and having its end portions mechanically connected with the respective supporting elements adjacent the crystal, the said yoke comprising two separatel metallic sections and an insulating section mechanically connecting the metallic sections.'

10. A piezoelectric crystal unit, comprising in combination, a crystal having metallic coatings on its opposite major faces, an insulating base, two supports on the -base at opposite sides of the crystal, two resilient supporting elements of conducting materlal mechanically and electrically connected at their respective outer ends with the ,Number REFERENCES CITED The following references are of record in the le of thisipatent:

STATES PATENTS Name Date 2,343,059 Hight v Feb. 29, 1944 

